STEP to STL: How to Convert STEP to STL Files
A how-to guide to this important part of the 3D printing process
STEP and STL are two of the most popular file formats used in 3D design and manufacturing. While similar, they’re not interchangeable; one is used for detailed and precise information for more complex parts, while the other is just a simple format that holds only the very basic data. Read on to find out which is which, why they’re both needed in additive manufacturing and how to make this conversion.
Before You Get Started
Generally, we recommend not converting your STEP files to STL for manufacturing. STEP files inherently contain more useful data, such as units and solid data. From a manufacturing side, we can use STEP files to create high-resolution mesh files for printing to ensure the highest print quality. STEP files are also typically required for subtractive manufacturing processes like CNC machining.
At Xometry, your STEP file will cover all your bases, including 3D printing, machining, sheet cutting, and more. So, if you're planning on using our services, there may be no need to convert your files at all! If you want to proceed anyway, then continue with the steps outlined in the sections below.
1. Open the STEP file
Once you’ve located the STEP file you want on your computer, right-click on it, and select “open with” to choose the CAD program. This will load up the file. There is another way to do this though the CAD software. Open the program, find the file, drag and drop it in, or load it up from within the program.
2. Open the file export settings
When your model is in the program, head over to the export options, which are usually under the File menu. This will typically be either “Save As…” or “Export.” No matter what you do, don’t just save the file under the standard “Save” option because that will just export it as it is.
4. Check for and configure STL export options
When you’ve clicked on the STL option, you’ll most likely be greeted with a box that allows you to check the export options. In SOLIDWORKS, for instance, clicking on “Options” will open an additional box for configuring the file. Whichever options you’re given, check them closely because they will affect your final file.
5. Save the file
Once you’re happy with the settings, go ahead and export your new STL file. It’s as simple as that. You can check to see how the conversion went by opening the new file in a 3D viewer or by uploading it to the Xometry Instant Quoting Engine® and using our online viewer to check it. That way, you can get a quote for any of our 3D printing processes.
What is STL?
STL (stereolithography/standard triangle language/standard tessellation language) is considered the standard file type for 3D printers in the mid-to-low price range. It was originally developed by 3D Systems when they first started making 3D printers and is also an ASCII format file. It works by splitting designs into lots of small triangles, with each one being defined by three points (x, y, z coordinates) that outline its shape. STL is a little on the older side and is known for being somewhat limited, mainly because it doesn’t contain any color or texture information and has a slightly more disjointed file structure. It does work well, however, for many tasks. It also contains information that tells the printer which side of the triangle should be facing outward. Here’s an example of an STL file:
What is STEP?
STEP is the acronym for Standard for the Exchange of Product Model Data, and it’s the most common and reliable cross-compatible data transfer tool between CAD and CAM (computer-aided design and computer-assisted manufacturing, respectively) systems. A STEP file can represent the full 3D design data and store all the details of the mechanical design, kinematics, and process planning, as well as metadata for a part or assembly. It works by providing 3D model construction data and metadata in an ASCII format defined by the STEP standard reference, ISO 10303-242:2014, and you’ll see it as “.STP” at the end of the file name. Many service providers like to use these files when providing quotes or offering advice, but clearly, it’s much more than a mere communication method.
What Programs can Open STEP Files?
There are several programs that can open STEP files. Any software that can open STEP files can convert them to a range of formats. Examples are:
- CAD Packages: CAD packages can all open .STP files. They also provide instructions on how to open .STP files, convert STEP files to SolidWorks, and more. Some of these CAD packages are: Prime and professional CAD packages: SolidWorks, Catia, Creo (formerly ProE), AutoDesk, Siemens NX (formerly UniGraphics). Second tier and free CAD: FreeCAD, Tinkercad, LibreCAD, ZBrush (formerly Sculptris), SketchUp, Fusion 360, FreeCAD, OnShape, and many more.
- .STP Viewers: .STP Viewers (both online and offline) offer a lightweight approach for those who need to see but not modify much. These include: Offline viewers: Geomagic Verify Viewer, GOM Inspect, VariCAD Viewer, gCAD 3D, IDA-STEP, STP Viewer, EnSuite-View, NIST STEP File Analyzer/Viewer, and more. Online viewers: FilePro Info, 3D Usher, STP Viewer - ABViewer 15, ShareCAD, and more.
What is the Best STEP to STL File Converter?
The best STEP to STL file converters are:
- Onshape Free: Onshape is a lightweight CAD package. When using the free version, however, the design/print files will be stored in a public directory in the cloud. This happens when the CAD capabilities are used or the files are saved in Onshape. To keep work private and secure, upload the STEP file into Onshape and convert STEP to STL, then save it locally.
- FreeCAD: This is a widely used and powerful CAD/CAM design package that serves well as a format converter. FreeCAD handles the widest range of formats. It also offers some great analysis, modification, and repair tools.
- GOM Inspect: This is another capable analysis and repair tool. There are many levels of function to explore that a regular user may find invaluable.
Why Should we Convert a STEP File to an STL File?
Converting a STEP file to an STL file is necessary when using a 3D printer that only recognizes STL to print a part. File conversion is required so that the slicer/printer setup can work with it.
How Long Does it Take to Convert a STEP file to STL?
Converting a STEP file to STL can take less than five seconds, depending on complexity and file size. For most files, setting up directories and uploading the files into the software can take longer.
What are the Differences Between STEP and STL formats?
The following table will help you understand the key differences between these two file types.
Frequently Asked Questions on STEP and STL
What programs can open STEP files?
There are lots of programs that do this, and they’ll usually allow you to convert the file, too. Some typical examples are STP viewers and CAD packages like SOLIDWORKS, Catia, Creo (formerly ProE), AutoDesk Fusion, Siemens NX (formerly UniGraphics), and many others. There’s also FreeCAD (which is also a converter), Tinkercad, LibreCAD, SketchUp, and Onshape—a lightweight cloud-based CAD package that stores your design and print files in a public directory in the cloud if you’re using the free version. There’s also a paid version which is more secure, and a Xometry add-in for it.
What’s the best converter?
There are plenty of good options to choose from to convert STEP to STL. We’ve already mentioned Onshape and FreeCAD—a powerful program that can handle lots of different formats and has some awesome analysis, modification, and repair tools and features. Another option is GOM Inspect which offers various function levels.
Are there any conversion problems to know about?
There are some, yes. For instance, you might lose detail or experience inaccurate scaling or incorrect resolution settings. Also, low-quality CAD models can actually cause the STL file to have some gaps, non-manifold edges, or mesh errors. If that happens, you’ll need to fix the problem before 3D printing.
Is it Possible to Convert an STL file to STEP?
Yes, it is possible to convert an STL file to STEP. There are available online tools that can help in file conversion.
How Xometry Can Help
If you need any clarification on the conversion or to learn more about the different file formats used in custom 3D printing services, please feel free to reach out to one of our representatives. At Xometry we actually accept many different native file formats, including STEP and STL! This makes it easy to upload your CAD files for instant quotes without going through conversions. In fact, we actually prefer users upload STEP files whenever possible as they can be used for quoting and manufacturing both additive processes like 3D printing, and subtractive processes like CNC machining. If you're looking for custom-made parts, you can get an instant quote by uploading your native files to the Xometry Instant Quoting Engine® and get started straight away.
Summary
Disclaimer
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